This invention relates to apparatus and method for the paired connection, sometimes referred to as "threading" of sheet piles having claws for the interconnection of the piles. More particularly, this invention relates to apparatus and method for the paired connection of sheet piles of Z-shaped or U-shaped cross-section for delivery to a construction site in connected pairs.
As is well known, Z-shaped or U-shaped sheet piles, which are individually formed, are often delivered to a construction site not only in individual pieces but in joined pairs. At the construction site the sheet piles are driven into the ground in joined pairs by means of appropriately designed pile drivers. The advantages inherent in the use of paired piles on job sites are well known.
If the advantages inherent in the use of paired piles are to be fully and economically exploited, connection of the individual piles into joined pairs must be achievable without significant difficulty. Several factors play roles in the connection of sheet piles, e.g. length of the piles, and the shape and dimensional tolerances of the claws which join the piles together. Particularly in the case of long piles, obstructions may be encountered in the process of driving or joining the piles together, often resulting in damage to the claws. The conventional approach in overcoming these obstruction difficulties is to dimension and operate the equipment used in the connection process at driving forces to overcome the obstruction by the increased application of force. This approach will often produce deformation in the claw area that becomes apparent only after completion of the connected pair of sheet piles. However, it is extremely difficult to repair damage of this type in finished paired sheet piling.